A US company has been given the green light to implant microchips in humans. It's intended to provide medical information ... but will it turn into a surveillance system?

How would you like to have the equivalent of a barcode built into your arm?

It would be convenient. A quick scan could save the need to show passports or ID cards. It would be handier than carrying cash or producing medical records.

And a particularly clever barcode would let people find you if you were lost or abducted.

Would it mean less hassle and more security? Or would it make you feel like a DVD tagged in the supermarket? Or like a criminal being monitored everywhere you went?

These are the questions being raised by the emergence of microchips that can be implanted in people's arms - with the technology moving from geeky future-gazing to a mainstream proposition.

VOTE RESULTS

Would you want a chip in your arm?

Yes

9.10%

For medical records only

7.86%

No way

83.04%

1527 Votes Cast

Results are indicative and may not reflect public opinion

This week, the United States Food and Drug Administration gave its approval for an implantable chip which can be used for medical purposes.

A microchip the size of a grain of rice can be inserted below the skin - and will carry an individual's medical records which can be read by a scanner.

The makers of the VeriChip say it will carry information that can save a patient's life during an emergency - such as details of medication, blood groups and allergies or if they have conditions such as diabetes.

In the UK, the British Medical Association says that it would see no ethical reason for not allowing such an implanted device, as long as it was proven to be safe and there was no coercion.

Security device

But there are other applications which are likely to be more contentious.

The implanted chip is about the size of a grain of rice

In a question and answer session, following the announcement of the FDA's approval, the Florida-based company behind the chip, Applied Digital, pointed to other commercial uses.

Security, which remains high on the US domestic agenda, is likely to be a key area for such microchips - offering the chance both to identify and track anyone carrying this type of implant.

Military bases, federal offices, prisons or nuclear plants were mentioned as places where the technology could be applied.

These internal microchips would be checked to regulate entry to secure locations. And once inside, scanners placed around the site would precisely locate the movements of each individual.

There would be no passes, ID cards or dog-tags, because all the information would be held on the chip lodged invisibly below the skin.

If this sounds far-fetched, access to a high-security crime database in Mexico is already being limited to the staff who have had a chip implanted.

While there might still be consumer resistance to getting part of a computer stuck in your arm - the underlying technology is already moving from the laboratory into the High Street.

Pet theory

"Radio frequency identification" chips have been attached to products in the supermarket to monitor shopping patterns.

Implanted chips could control entry to secure buildings

And in response to fears about child abductions, several schools in Japan have experimented with tracking chips being put into pupils' clothing.

Even if we don't want to put microchips into ourselves, we're not squeamish about animals. Following the same basic principle, chips have been injected into millions of pets and farm animals.

But there have been concerns about how such technology could be abused and become a form of undisclosed surveillance, with movements and activities electronically monitored.

Last week, the American Civil Liberties Union (ACLU) urged lawmakers in Virginia not to put such trackable chips into drivers' licences - arguing that it would breach people's privacy.

Such devices would allow the authorities "to sweep up the identities of everyone at a political meeting or protest march," says the ACLU.

In considering the potential threat to civil liberties, the UK's data watchdog, the Information Commissioner, says it is important to look at the underlying principles, rather than only the technology.

Threats to privacy

And a spokesperson says that much of the capacity to track people already exists - the question is how this information is used.

This "chipped" cat was registered in the US, but found in Oxfordshire

If anyone wanted to introduce such a system into the UK, there would need to be assurances that the information was not being used for any purpose other than clearly declared.

The Information Commissioner's office pointed to the current example of delivery drivers who are tracked using their mobile phones. This is deemed acceptable, as long it is being used for very specific business purposes.

But civil liberties campaigners, Liberty, warn that the arrival of such tracking chips needs to be matched by a tougher legal framework to protect people's privacy.

Spokesperson Barry Hugill says the law is lagging behind this accelerating technology - and that more questions need to be asked about how the information gathered will be used and protected.

"When the technology is so powerful it seems wrong that it should be left to multi-nationals to decide how it should be controlled."

Even though tracking chips are intended for legitimate commercial purposes, there are concerns about how this detailed information about people's movements could be collated and who might have access.